Process for producing homogeneous articles of any desired form out of pure tungsten.



-. 1 mi TED STATESPATENT OFFICE.

o'r'ro VOIGTLANDER, or ESSEN-ON-THE-RUHR, GERMANY.

I No Drawing,

PROCESS FOR PRODUCING HOMOGENEOUS ARTICLES OF ANY DESIRED FORM OT I'I. OF I PUB-E TUNGSTEN.

To all whom it may concern Y Be it known that I, Orro VOIG'ILKYDER,

manufacturer,.citizen .of the German um.- pire, residing at Essen-on-the-Ruhr, Germany, have invented certain new and useful Improvements in Processes for Producing Homogeneous Articles of Any Desired Form Out of Pure Tungsten, of which the following is a specification.

As is well known tungsten 1s chlefly precipitated out of its ores'by caustic potashand converted intolVO The oxid is reduced to metal by heating in the presence of carbon or a current of hydrogen. By so doing a metal powder of a greater or lesser degree of purity is obtained.

Heretofore no process was known which hen however small quantities of homo- J I geneous tungsten were required for certain purposesit was 'usual to subject V0,, or an oxulcontaining but llttle O to a high pressure so as to form rods or other shapes,

whereupon the bodies so formed were fur-1 ther reduced in a current of hydrogen, and

finally said bodies were heatedas high as possible by tlmelectric current, in order to cause the powder to unite.

Apart from the fact that this process, be-

ing too expensive, cannot be used for most purposes. it is only possible to use the same for making articles of very small section, because the strength of current required for uniting or sintering the same increases with the section which 'is accordingly restricted to a few millimeters.

Tungsten has indeed been successfully introduced into cast-iron, steel, gun-metalthus to produce alloys of tungsten by means .of the aluminium thermic process (see Minet, Die Ge winmmg (Zes Aluminium 1902, page 122, published by \Vilhelm Knappe, Halle on the Saale, Germany), but the production of pure tungsten in homogeneous pieces was not successful. Further the experiments carried out by Stavenhagen, Borchers, \Veiss Martin (see Mennicke, Metallurgz'e des Wolfmm, 1911, pages 194-195 published by M.

Specification of Letters Patent.

Patented May 1, 1917.

Application filed March 22, 1913. Serial No. 756,214.

Krayn, Berlin,.Germany) did not lead to any solution of the problem of producing homogeneous tungsten in pieces of any desired size, not even by using the aluminium thermic process.

The tungsten bodies obtained by said experiments were either too small or too porous to be used, or the product was not pure.

The experiments made by Borchers (see Mennicke, 811 pm, page 1 5) to mix a mixture of V0 and A1 with columetric parts of liquid air for the purpose of increasing the temperature of the reaction and igniting said mixture, only resulted in but small quantities of reguline tungsten;

By'detailed experiments the inventor of the present process has ascertained that the heat produced in the reaction of the mlxture of VVO ,A1 when ignited sufiices 'to reduce W0 but the quantity of heat produced thereby does not even approximately suflice in order to evaporate or dissolve allv auxiliary or foreign substances and to melt the metal powder into a homogeneous body.

These experiments resulted in the new process.

This process is characterized by a mixture consisting, for example, of WO and Al being placed in a tube or receptacle of any desired form, which is burnt in a. furnace of any suitable construction, heated to as high a degree as possible so that by the heat of reaction of the mixture combined with the heat of the furnace the metal is separated from the foreign particles contained therein and it is completelymelted so as to form a homogeneous body.

This process enables the production of articles of pure homogeneous tungsten having a weight amounting to many kilograms, which can then be Wrought, pressed or worked in any other manner suitable for the purpose.

As, according to the new process, the form of the article is only dependent upon the form of the receptacle in which the mixture is introduced into the furnace, articles which do not require any or'but little finish, suchas crucibles, etc., can be produced at once. I believe I am the first to produce founded or cast tungsten, or to make any cast article of tungsten.

In carrying out thenew process the oxidation ofthe finished article can be avoided by a current of indifierent gas being passed through the receptacle in which the metal is.

placed when introduced into the furnace. It has already been proposed in carrying out the aluminium thermic process to heat the reacting substance in a crucible or fur nace from the outside until the reaction takes place. 'But this proposal only related to the introduction of the reaction by out side heating in producing reguline chromic metal. 1

By the new process not only WO but all other lower oxids can be Worked into pure homogeneous metal, only the requisite quantity of the aluminium to be added having to be determined.

What I claim and desire to' secure by Letters Patent of the United States is v 1. The process of producing metallic tungsten in homogeneous form, which comprises reacting on an oxid of tungsten with metallic aluminium in the presence of heat suflicient to reduce the oxid to compact metal and melt the metal, vsaid heat being 'in addition to .the heat of reaction.

2. The process of producing metallic tungsten in homogeneous form, which com-.

prises reacting on the tri-oxid of tungsten with metallic aluminium While subjecting the reacting mixturaduring the entire reaction to a high degree of external heat sufficient to melt the metal.

The process of producing solid tungsten metal, which comprises placing a mixture of tungsten oxid and metallic aluminium in a suitable receptacle and heating the receptacle to a high temperaturethe heat of the receptacle and the heat of reaction the reaction, suificient to melt the tungsten into a solid regulus of pure tungsten metal.

In testimony whereof I affix my signature in presence of two Witnesses.

OTTO VOIGTLANDER. [n s.]

Witnesses:

HELEN NUFER, ALBERT NUFER. 

